中文摘要：

处理单基线全球导航卫星系统观测数据可获取位置、时间、大气延迟等信息,其应用包括相对定位、时频传递等。为实现实时性,常采用卡尔曼滤波递归地估计各类参数;为确保可靠性,还需形成一组独立的双差模糊度,并将其正确地固定为整数。实践中,滤波函数模型较常采用双差观测方程（即双差滤波模型）。若在当前历元原先的参考星不再可视时,双差滤波模型则需要定义新的参考星,并＂映射＂双差模糊度预报值以确保滤波连续。此外,双差滤波模型所计算的接收机相位钟差估值吸收了对应于参考星的站间单差模糊度,因此当参考星变换后可能会发生＂整周跳跃＂。在仍将双差模糊度作为一类可估参数的前提下,本文推导出以站间单差观测方程为滤波函数模型的算法（单差滤波模型）,并证明了其与双差滤波模型具备理论上的等价性和实施上的差异性。与双差滤波模型相比,单差滤波模型不再需要＂映射＂双差模糊度预报值等运算,从而具备了更高的计算效率和灵活性;单差滤波模型所提供的接收机相位钟差估值也不受＂整周跳跃＂的影响,因此特别有利于频率传递应用。

英文摘要：

Single-baseline global navigation satellite system（GNSS）data are able to be processed into a batch of parameters such as positions,timing information as well as atmospheric delays.The applications of relevance,therefore,consist of relative positioning,time and frequency transfer and so forth.To achieve real-time capability,these parameters are usually estimated by means of Kalman-filter.Moreover,the reliability of these parameters can be further strengthened by forming and then successfully fixing a set of independent double-differenced（DD）integer ambiguities.For this purpose,the filter function model is commonly set up based on the DD observation equations（DD filter model）.In order to preserve the continuity of the filter,DD filter model needs to explicitly refer to another pivot satellite once the previous one becomes invisible.This thereby implies that,before being predicted to the next epoch,the former filtered DD ambiguity vector has to be＂mapped＂with respect to the newly-defined pivot satellite.In addition to that,the estimated receiver phase clocks using DD filter model may soak up distinct between-receiver single-differenced（SD）ambiguities belonging to different pivot satellites and would thereby be subject to apparent＂integer jumps＂.In this contribution,SD observation equations involving estimable DD ambiguity parameters are alternatively selected as the filter function model（SD filter model）.Our analyses suggest that,both DD and SD filter models are equivalent in theory,but differ from each other as far as their implementations are concerned.Typically,for SD filter model,no effort should be made to map DD ambiguities,thus implying less intensive computational burden and better flexibility than DD filter model.At the same time,receiver phase clocks determined by SD filter model are free from ＂integer jumps＂and thus are particularly beneficial for frequency transfer.